xbmc: handle SIGTERM

In some situations, due to deadlocks or crashes, xbmc fails to exit properly in
CApplication::Stop(), so  g_powerManager.Reboot() / g_powerManager.Powerdown() never gets
called, that's a big no-no for openelec as our users can't shutdown or reboot.
There are few addons reported to cause this behaviour: trakkt.tv, watchdog, weather.underground.

I've also noticed that sometimes new threads (FileCache ??) get started AFTER
CApplication::Stop() is called, delaying shutdown with 1+ minute (2 curl timeoouts?).
The problem seems to be in CJobManager::CancelJobs() but I am too lame to understand where,
why, and how to fix it.

To me, it seems best to let systemd handle it. systemd sends SIGTERM, then waits
TimeoutStopSec=xx seconds then sends SIGKILL,s so dont call g_application.Stop() from
ApplicationMessenger as it can not be trusted. save the requested exitcode instead
(that's required for CEC to switch off the tv) and do it from a simple SIGTERM handler instead.

CEC thread has enough time (5 seconds in xbmc.service) to switch of the TV after receiving OnQuit.
As a side "effect", now guisettings.xml will ALWAYS be saved, even if shutdown / rebooot
is requested externaly (ssh, 3rdparty script).
openssl: update to openssl-1.0.1h

Signed-off-by: Stephan Raue <stephan@openelec.tv>